Reprogrammable logic device resistant to radiations

Abstract

The invention relates to a reprogrammable logic device comprising a plurality of elementary patches, each patch comprising: at least one logic block configurable by one or more volatile memory cells storing configuration data; and a memory comprising: a plurality of non-volatile memory cells storing refresh data, each non-volatile memory cell comprising first and second resistance-switching elements, each being programmable so as to have one of a first and of a second resistance value representative of the refresh data; and a read-write circuit adapted for periodically refreshing the configuration data on the basis of the refresh data.

The invention claimed is: 
     
       1. A reprogrammable logic device comprising a plurality of tiles, each tile comprising:
 at least one logic block ( 108 ) adapted to perform a logic function, one or more interconnections of the logic block and the logic function applied by the logic block being configurable by configuration data stored by one or more volatile memory cells ( 322 ) storing configuration data; and 
 a memory ( 116 ) comprising:
 a plurality of non-volatile memory cells ( 402 ) storing refresh data, each non-volatile memory cell comprising first and second resistance switching elements ( 520 ,  522 ) each programmable to have one of first and second resistance values (Rmin, Rmax) representative of said refresh data; and 
 read-write circuitry ( 408 ) adapted to periodically refresh said configuration data based on said refresh data at intervals of between 1 and 100 milliseconds. 
 
 
     
     
       2. The reprogrammable device of  claim 1 , wherein said one or more volatile memory cells ( 322 ) are DRAM (Dynamic Random Access Memory) cells each comprising a capacitance ( 334 ) for storing a voltage state representative of said configuration data. 
     
     
       3. The reprogrammable device of  claim 1 , wherein each of a first and a second of the non-volatile memory cells is coupled to a first and a second node ( 508 ,  510 ) of the read-write circuitry, and the read-write circuitry is adapted to periodically refresh the configuration data of a first of the volatile memory cells based on the refresh data stored by the first non-volatile memory cell, and to periodically refresh the configuration data of a second of the volatile memory cells based on the refresh data stored by the second non-volatile memory cell. 
     
     
       4. The reprogrammable device of  claim 1 , wherein each of said volatile memory cells comprises a selection transistor ( 330 ), and each of said first and second resistance switching elements ( 520 ,  522 ) is coupled in series with a further selection transistor ( 524 ,  526 ). 
     
     
       5. The reprogrammable device of  claim 1 , wherein a refresh data bit stored by each of said non-volatile memory cells ( 402 ) is determined by the relative resistances of the first and second resistance switching elements ( 520 ,  522 ). 
     
     
       6. The reprogrammable device of  claim 1 , wherein said configuration data controls one or more of:
 the data values in a lookup table ( 310 ) of said logic block ( 108 ); 
 the selection of input lines ( 104 ) of said logic block; and 
 the selection of output lines ( 106 ) of said logic block. 
 
     
     
       7. The reprogrammable device of  claim 1 , wherein said memory further comprises an activation module ( 410 ) for selectively activating said memory. 
     
     
       8. The reprogrammable device of  claim 1 , wherein said read-write circuitry ( 408 ) comprises a latch comprising first and second transistors ( 504 ,  506 ), wherein a first terminal of the first resistance switching element of each of said plurality of non-volatile memory cells is coupled to said first transistor, and a first terminal of the second resistance switching element of each of said plurality of non-volatile memory cells is coupled to said second transistor. 
     
     
       9. The reprogrammable device of  claim 8 , further comprising a control circuit ( 204 ), wherein said first transistor ( 504 ) is coupled between a first storage node ( 802 ) and a first supply voltage (GND, V DD ), said second transistor ( 506 ) is coupled between a second storage node ( 806 ) and said first supply voltage (GND, V DD ), a control terminal of said first transistor being coupled to said second storage node, and a control terminal of said second transistor being coupled to said first storage node, and wherein said control circuit is adapted to apply, during a programming phase of the first resistance switching element, a second supply voltage to said second storage node to active said first transistor, and then to apply said second supply voltage to said first storage node to generate a first write current (I A ) through said first transistor and said first resistance switching element. 
     
     
       10. The reprogrammable device of  claim 9 , wherein said control circuit is further adapted to isolate said second storage node from said second supply voltage, and then to apply, during a programming phase of the second resistance switching element, said second supply voltage to said second storage node to generate a second write current (I B ) through said second transistor and said second resistance switching element. 
     
     
       11. The reprogrammable device of  claim 9 , wherein said memory further comprises a third transistor ( 804 ) coupling said first storage node to said second supply voltage and a fourth transistor ( 808 ) coupling said second storage node to said second supply voltage. 
     
     
       12. The reprogrammable device of  claim 11 , wherein said third transistor ( 804 ) is adapted to have a lower threshold voltage than said first transistor ( 504 ) and said fourth transistor ( 808 ) is adapted to have a lower threshold voltage than said second transistor ( 506 ). 
     
     
       13. The reprogrammable device of  claim 9 , wherein said read-write circuitry further comprises a fifth transistor ( 512 ) coupled between said first and second storage nodes. 
     
     
       14. The reprogrammable device of  claim 1 , further comprising:
 a plurality of said tiles ( 102 ); and 
 a controller ( 204 ) adapted to control at least the activation of said memory of each of said tiles and the refreshing of the configuration data of each of said tiles. 
 
     
     
       15. The reprogrammable device of  claim 1 , wherein said first and second resistance switching elements are one of:
 thermally assisted switching (TAS) elements; 
 oxide resistive elements; 
 conductive bridging elements; 
 phase change elements; 
 programmable metallization elements; 
 spin transfer torque elements; and 
 field-induced magnetic switching (FIMS) elements. 
 
     
     
       16. A method of refreshing a reprogrammable device comprising a plurality of tiles ( 102 ), each tile comprising at least one logic block ( 108 ) adapted to perform a logic function, comprising one or more inputs coupled to one or more volatile memory cells ( 322 ) storing configuration data, the method comprising:
 periodically refreshing, at intervals of between 1 and 100 milliseconds, said configuration data based on refresh data stored in non-volatile memory cells ( 402 ) of a memory ( 116 ), wherein each non-volatile memory cell comprises first and second resistance switching elements ( 520 ,  522 ) each programmable to have one of first and second resistance values (Rmin, Rmax).